In a conventional assembly structure, for example, a sleeve is attached to a an upright erect post outside, a collar is fitted to the sleeve attached to the post outside from the side of the post, and both ends of a holder provided at a corner of a shelf plate is extended laterally by resisting the elasticity. Further, both end bumps of the holder are fitted into the recesses formed at the collar lateral side from the side of the collar and are engaged with the both lateral recesses of the collar, and the holder is mounted and assembled on the protrusion protruding to the lower end side of the collar, and the assembly type shelf of patent document 1 is formed.
However, when attaching or detaching the holder on the collar lateral side, the both ends of the holder are extended laterally by resisting the elasticity, but if the holder is fitted to the collar from the side or from above, when a tensile stress is applied to the shelf plate having the holder and the post having the collar in the horizontal direction, the both ends of the holder are likely to be extended laterally by resisting the elasticity, and the collar may be detached from the holder, and sufficient structural strength for maintaining the assembled state of shelf may not be obtained.
In an assembly booth, alternatively, by mutually connecting protruding ends of edge clamps fixed to opposite edges of extension panel and corner panel, tightening and fixing with tightening members, edge clamps and tightening members are used for mounting shelf plates on braces fitted to the tightening members as disclosed in patent document 2.
However, after mutually connecting and fixing the protruding ends of edge clamps by rotating the operation levers of the tightening members fitted to the protrusions of the edge clamps, shelf plates must be mounted on the braces fitted to the tightening members, and it takes time and labor when attaching or detaching shelf plates, or when changing the height. For example, the tightening force of the tightening members is gradually lowered due to wear or deformation, and necessary strength for maintaining the assembly structure may not be obtained.
Patent document 1: Japanese Patent No. 3469161
Patent document 2: Japanese Patent Publication No. H9-302818